The point is you don't need to run upgraded injectors, the RS4 PRV gives the stock injectors the little extra space in fueling needed and as long as your tune accounts for that it will be fine (as Stranded said), but if you are looking to really get power and "max" out a K04 or F23T you do need to upgrade them (as Strieg said).
In the end it just depends on what your trying to do and how much power your trying to make. Technically all you need is the RS4 PRV and Golf R/3 bar map sensor (on a TSI), but you will be limiting what kind of numbers you can make with it and also pushing your hardware fairly hard. As stated above an upgraded intercooler is highly recommended, but like I said it really just depends on what your end goal is. I believe in over building, easier on your system as a whole and leaves room to grow down the line